Why is it all red?

My intake manifold on my 4.3 was leaking coolant everywhere. I took it out along with the valve covers. One side looks normal. The rest is red. I put up some pictures. Can any one tell me what’s going on here? Thanks.

My guess is someone added an oil additive at some point to the oil. Hopefully they didn’t use transmission oil.

I hope not. Why would it only be on one side?

Did one of the heads get replaced recently? Things look pretty clean at least.

I don’t think so. I’ve put maybe 20,000 miles on it. The last owner didn’t mention anything

Looks to me like one side got overheated and cooked the residual oil coating the parts on that side.

PCV valve on one cover, air inlet on the other?
One side has more fumes than the other.
How often do you change oil?

Maybe. I’ve never let it overheat badly.

I’m pretty good about changing oil. Usually around 3,000 miles